Package se.liu.ida.hefquin.engine.queryplan.executable.impl.ops

Class ExecOpNaiveNestedLoopsJoin

java.lang.Object

se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.BaseForExecOps

se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.BinaryExecutableOpBase

se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.ExecOpNaiveNestedLoopsJoin

All Implemented Interfaces:

StatsProvider, BinaryExecutableOp, ExecutableOperator

public class ExecOpNaiveNestedLoopsJoin
extends BinaryExecutableOpBase

Attention, this is a purely local implementation of the nested loops join algorithm---nothing fancy, no requests to federation members or anything. Instead, this algorithm first consumes the whole first input and materializes it into a list. Thereafter, it performs a local nested loops join in which the outer loop iterates over the second input and the inner loop (repeatedly) iterates over the list with the first input. It is certainly better to use the ExecOpHashJoin instead. Instead of simply putting all left-input solution mappings into a list, the hash join puts them into a hash index which can than be probed into for each right-input solution mapping.

Field Summary

Fields

Modifier and Type	Field	Description
protected final List<SolutionMapping>	inputLHS

Fields inherited from class se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.BinaryExecutableOpBase

timeAtCurrentLeftProcStart, timeAtCurrentRightProcStart

Fields inherited from class se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.BaseForExecOps

collectExceptions

Constructor Summary

Constructors

Constructor	Description
ExecOpNaiveNestedLoopsJoin(boolean collectExceptions)

Method Summary

Modifier and Type	Method	Description
protected void	_processBlockFromChild1(IntermediateResultBlock input, IntermediateResultElementSink sink, ExecutionContext execCxt)	Implementations of this function need to process the given input block coming from the first operand and send the produced result elements (if any) to the given sink.
protected void	_processBlockFromChild2(IntermediateResultBlock input, IntermediateResultElementSink sink, ExecutionContext execCxt)	Implementations of this function need to process the given input block coming from the second operand and send the produced result elements (if any) to the given sink.
protected void	_wrapUpForChild1(IntermediateResultElementSink sink, ExecutionContext execCxt)	Implementations of this function need to finish up any processing related to the input coming from the first operand and send the remaining result elements (if any) to the given sink.
protected void	_wrapUpForChild2(IntermediateResultElementSink sink, ExecutionContext execCxt)	Implementations of this function need to finish up any processing related to the input coming from the second operand and send the remaining result elements (if any) to the given sink.
int	preferredInputBlockSizeFromChild1()	Returns the preferred block size of input blocks that are passed to this executable operator from the first operand.
int	preferredInputBlockSizeFromChild2()	Returns the preferred block size of input blocks that are passed to this executable operator from the second operand.
boolean	requiresCompleteChild1InputFirst()	Returns true if this operator is implemented based on the assumption that the COMPLETE input from the first operand has been sent to it before input from the second operand is sent.

Methods inherited from class se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.BinaryExecutableOpBase

createStats, getStats, processBlockFromChild1, processBlockFromChild2, resetStats, wrapUpForChild1, wrapUpForChild2

Methods inherited from class se.liu.ida.hefquin.engine.queryplan.executable.impl.ops.BaseForExecOps

getExceptionsCaughtDuringExecution, recordExceptionCaughtDuringExecution

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface se.liu.ida.hefquin.engine.queryplan.executable.ExecutableOperator

getExceptionsCaughtDuringExecution

Field Details

inputLHS

protected final List<SolutionMapping> inputLHS

Constructor Details

ExecOpNaiveNestedLoopsJoin

public ExecOpNaiveNestedLoopsJoin(boolean collectExceptions)

Method Details

preferredInputBlockSizeFromChild1

public int preferredInputBlockSizeFromChild1()

Description copied from interface: BinaryExecutableOp

Returns the preferred block size of input blocks that are passed to this executable operator from the first operand. A query planner may use this number as an optimization hint but it does not have to use it.

preferredInputBlockSizeFromChild2

public int preferredInputBlockSizeFromChild2()

Description copied from interface: BinaryExecutableOp

Returns the preferred block size of input blocks that are passed to this executable operator from the second operand. A query planner may use this number as an optimization hint but it does not have to use it.

requiresCompleteChild1InputFirst

public boolean requiresCompleteChild1InputFirst()

Description copied from interface: BinaryExecutableOp

Returns true if this operator is implemented based on the assumption that the COMPLETE input from the first operand has been sent to it before input from the second operand is sent. An example of an operator that may return true here is a hash join (which first needs to add all result elements from the first operand into its hash table and, then, can start consuming the result elements from the second operand by probing into the hash table). In contrast, a symmetric hash join (which has two hash tables and can consume result elements from both inputs in any order) would return false. Operators that return true here may throw an IllegalStateException if their methods BinaryExecutableOp.processBlockFromChild2(IntermediateResultBlock, IntermediateResultElementSink, ExecutionContext) or BinaryExecutableOp.wrapUpForChild2(IntermediateResultElementSink, ExecutionContext) are called before BinaryExecutableOp.wrapUpForChild1(IntermediateResultElementSink, ExecutionContext) has been called.

_processBlockFromChild1

protected void _processBlockFromChild1(IntermediateResultBlock input,
 IntermediateResultElementSink sink,
 ExecutionContext execCxt)

Description copied from class: BinaryExecutableOpBase

Implementations of this function need to process the given input block coming from the first operand and send the produced result elements (if any) to the given sink. If an exception occurs while processing the input block, this exception needs to either be collected or be thrown, depending on whether BaseForExecOps.collectExceptions is set to true.

Specified by:

_processBlockFromChild1 in class BinaryExecutableOpBase

_wrapUpForChild1

protected void _wrapUpForChild1(IntermediateResultElementSink sink,
 ExecutionContext execCxt)

Description copied from class: BinaryExecutableOpBase

Implementations of this function need to finish up any processing related to the input coming from the first operand and send the remaining result elements (if any) to the given sink. If an exception occurs during this process, then this exception needs to either be collected or be thrown, depending on whether BaseForExecOps.collectExceptions is set to true.

Specified by:

_wrapUpForChild1 in class BinaryExecutableOpBase

_processBlockFromChild2

protected void _processBlockFromChild2(IntermediateResultBlock input,
 IntermediateResultElementSink sink,
 ExecutionContext execCxt)

Description copied from class: BinaryExecutableOpBase

Implementations of this function need to process the given input block coming from the second operand and send the produced result elements (if any) to the given sink. If an exception occurs while processing the input block, this exception needs to either be collected or be thrown, depending on whether BaseForExecOps.collectExceptions is set to true.

Specified by:

_processBlockFromChild2 in class BinaryExecutableOpBase

_wrapUpForChild2

protected void _wrapUpForChild2(IntermediateResultElementSink sink,
 ExecutionContext execCxt)

Description copied from class: BinaryExecutableOpBase

Implementations of this function need to finish up any processing related to the input coming from the second operand and send the remaining result elements (if any) to the given sink. If an exception occurs during this process, then this exception needs to either be collected or be thrown, depending on whether BaseForExecOps.collectExceptions is set to true.

Specified by:

_wrapUpForChild2 in class BinaryExecutableOpBase